Rats, e.g., have particularly good memories and a relatively high intelligence quotient. They are able to connect the toxic effect of rapidly-acting poisons with the type and position of employed bait, and they warn other rats.
Rodenticides comprising anti-coagulating or anti-clotting agent(s) have the advantage that hemorrhaging is produced several days after repeated administration and is thus not readily attributed by the rodents to the effect of the poison. Rodent corpses are not generally found about a feeding place so as to alarm other rats.
However, such rodenticides have a serious deficiency; the poison(anti-coagulant or anti-clotting agent) ordinarily fails to have lethal effect unless consumed in sufficient quantity a number of times (cumulative effect) by the same rodent. Experience has shown that this factor considerably reduces the success of anti-coagulant-based rodenticides for combatting and/or eliminating rodents.
ORAL ANTICOAGULANTS [CF., E.G., Goodman, Louis S., and Gilman, Alfred, "The Pharmacological Basis of Therapeutics" ; third edition, pages 1451 and 1452, The Macmillan Company, 1965] and hemorrhagic-lesion-producing drugs [cf., e.g., "Physicians' Desk Reference" ; 27th edition, pages 756 (right column) and 1000 (left column), 1973] are known.